Motor Drive IC Thermal Load Distribution via Segmented Braking
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Solution Overview
Problem
Existing opening/closing body drive devices suffer from reduced lifespan of integrated circuits due to thermal loads caused by switching losses during braking operations, as they typically require simultaneous activation of switching elements in both forward and reverse rotations, leading to uneven thermal distribution and potential overheating.
Innovation Solution
The drive unit incorporates freewheeling diodes in parallel with switching elements and a control unit that selectively activates specific switching elements for braking based on rotation direction, ensuring that different integrated circuits handle braking loads, thereby reducing thermal accumulation and extending circuit lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is braked by turn-on driving the second and fourth switching elements during forward or reverse rotation, then effective braking is achieved, but thermal loads of the integrated circuits increase and lifespan is reduced
Solution Approach 1:
The H bridge circuit is divided into two separate integrated circuits: the first integrated circuit contains the first and second switching elements, while the second integrated circuit contains the third and fourth switching elements. This segmentation allows the braking operation to be performed by only one integrated circuit at a time, distributing the thermal load and preventing both circuits from experiencing high temperatures simultaneously, thereby extending their operational lifespan.
2Force
If the second and fourth switching elements are turned on for braking during motor rotation, then braking force is applied, but switching losses generate thermal loads that reduce integrated circuit life
Solution Approach 1:
By segmenting the switching elements into two separate integrated circuits, the braking operation (which generates switching losses and thermal load) is assigned to only one integrated circuit at a time. This reduces the cumulative switching losses experienced by each individual circuit, as each circuit alternates between driving and braking operations, thereby reducing overall energy loss and thermal accumulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces thermal loads on integrated circuits by selectively activating switching elements during braking, preventing overheating and prolonging the life of the circuits, while maintaining effective motor control for opening and closing operations.
Implementation Method 1
first to fourth freewheeling diodes are incorporated in or attached in parallel to the first to fourth switching elements
Data Source
AI summary
An opening/closing body drive device includes: a motor which opens or closes an opening/closing body; a drive unit which rotates the motor; and a control unit which controls the drive unit. The drive unit includes first and second integrated circuits having first and second switching elements and third and fourth switching elements which are connected to each other in series with respect to a power source and connection points of which are connected to one and the other terminals of the motor, respectively. The control unit turn-on drives only the second switching element when braking the motor during the forward rotation and turn-on drives only the fourth switching element when braking the motor during the reverse rotation, or turn-on drives only the third switching element when braking the motor during the forward rotation and turn-on drives only the first switching element when braking the motor during the reverse rotation.